Layered vanadyl (IV) nitroprusside: Magnetic interaction through a network of hydrogen bonds

HERNÁNDEZ OSIRY; DIEGO MAURICIO GIL; FERNANDO POMIRO; RAÚL ERNESTO CARBONIO; E.L. VARETTI; ALEJANDRO RODRÍGUEZ; EDILSO REGUERA; AIDA BEN ALTABEF

JOURNAL OF SOLID STATE CHEMISTRY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2016 vol. 239 p. 159 - 164

0022-4596

The hydrogen bond and π-π stacking are two non-covalent interactions able to support cooperative magnetic ordering between paramagnetic centers. This contribution reports the crystal structure and related magnetic properties for VO[Fe(CN)5NO]·2H2O, which has a layered structure. This solid crystallizes with an orthorhombic unit cell, in the Pna21 space group, with cell parameters a=14.1804(2), b=10.4935(1), c=7.1722(8) Å and four molecules per unit cell (Z=4). Its crystal structure was solved and refined from powder X-ray diffraction data. Neighboring layers remain linked through a network of hydrogen bonds involving a water molecule coordinated to the axial position for the V atom and the unbridged axial NO and CN ligands. An uncoordinated water molecule is found forming a triple bridge between these last two ligands and the coordinated water molecule. The magnetic measurements, recorded down to 2 K, shows a ferromagnetic interaction between V atoms located at neighboring layers, with a Curie-Weiss constant of 3.14 K. Such ferromagnetic behavior was interpreted as resulting from a superexchange interaction through the network of strong OH····OH2O, OH····NCN, and OH····ONO hydrogen bonds that connects neighboring layers. The interaction within the layer must be of antiferromagnetic nature and it was detected close to 2 K.